Policy Issues

Mental Illness

There is no categorical ban on the execution of people with mental illness. A small number of states have laws that create an exemption for some seriously mentally ill defendants.

Resources on Severe Mental Illness and Death Penalty

Resources on Severe Mental Illness and Death Penalty

American Bar Association Death Penalty Due Process Review Project

DPIC Report: Battle Scars

DPIC Report: Battle Scars

Military Veterans and the Death Penalty (Features information on PTSD and other combat-related mental health problems)


The U.S. Supreme Court has said a defendant’s mental illness makes him or her less morally culpability and must be taken into consideration as an important reason to spare his or her life. However, as was initially the case with intellectual disability and young age, the Court has not barred the death penalty for those with serious mental illness. When the Court prohibited the death penalty for the intellectually disabled and for juveniles, it found that they were members of identifiable groups who have diminished responsibility for their actions and hence should not be considered the worst and most culpable defendants. Many mental health experts believe that people with severe mental illness such as schizophrenia and bipolar disorder may have similar cognitive impairments that interfere with their decision-making. The American Psychiatric Association and the American Bar Association, among others, have called for a ban on the death penalty for those with severe mental illness.

Some defendants are so mentally ill as to lack all understanding of their crime and its consequences and may be considered mentally incompetent. Such individuals may be unfit to stand trial or be found not guilty by reason of insanity. If they are convicted and become incompetent while on death row, they cannot be executed, under earlier Supreme Court precedent. However, most people with mental illness — including many with severe mental illness — are not mentally incompetent.

Mental health issues have broad impact in death-penalty cases. One in ten prisoners executed in the United States are “volunteers” — defendants or prisoners who have waived key trial or appeal rights to facilitate their execution. Mental illness also affects defendants’ decisions to represent themselves, their ability to work with counsel, and jury’s perceptions of their motives and whether they pose a future danger to society if they are sentenced to life in prison.

At Issue

There are at least three hurdles to excluding the severely mentally ill: 1. Unlike age and intellectual ability, it is difficult to define the class of mentally ill defendants who should be exempted and to determine whether their illness affected their judgment when they offended. 2. States have so far been reluctant to adopt such bans, though society continues to evolve in terms of its understanding of mental illness. 3. The membership of the Supreme Court has shifted since some of the earlier exemptions were decided. Nevertheless, the prior decisions could serve as important precedents, capable of being extended to the mentally ill.

What DPIC Offers

DPIC has tracked the various state legislative efforts to address the mental illness issue. It frequently highlights instances in which mentally ill defendants receive unfair death-penalty trials, face execution, or have been granted clemency or other relief. It also gathers statements from relevant leaders in the mental health field regarding this issue.

News & Developments

Intellectual Disability

Mar 08, 2023

Texas Withdraws Execution Date to Allow for Mental Competency Consideration

A Grayson County, Texas court has with­drawn the April 5, 2023 exe­cu­tion date for Andre Thomas (pic­tured), a seri­ous­ly men­tal­ly ill pris­on­er whose legal team request­ed more time to demon­strate that Thomas is incom­pe­tent to be exe­cut­ed. While incarc…

Intellectual Disability

Feb 20, 2023

Upcoming Executions Raise Concerns about Mental Illness and the Death Penalty

The cas­es of two defen­dants fac­ing immi­nent exe­cu­tion raise con­cerns about the appro­pri­ate­ness of death sen­tences for those with severe men­tal ill­ness or sharply-lim­it­ing men­tal dis­abil­i­ties. Andre Thomas is sched­uled for exe­cu­tion on April 52